g-ritzner



4 (Model.) l 4 sheets-sheet 2.

M. C. GRITZNBR.

Sewing AMachine. No. 243,444.` Patented June 28, |881.

(Model.) 4 Sheets-Sheet 3.

`MQC. GRITZNER.

- Sewing Machine. No. 243,444. Y Patented lulgg, 1881.

02m Iowfmr 4M www@ www? N. PETERS. Pham Litmgmpm vlamingen. u. C.

(lod l.) 4 Sheets-Sheet 4;

1ML-o. GRITZNER.

Sewmg Maohlne. N0. 243,444'. Patefed .lune 28, |881.

lUNITED STATES PATENT erica.

MAX C. GRITZNER, OF BADEN, GERMANY.

sEwiNG-MACHINE.

SPECIFICATION forming part of Letters Patent No. 243,444, dated June 28, 1881. Application tiled June 11, 1880. (Model.) Patented in Germany December 20, 1878, and in England August 25, 1879.

To all lwhom it may concern Y' Be it known that I, MAX CHARLEs GRI'rZ- NER, of Baden, Germany, have invented a new and useful Improvement in Sewing-Machines, which invention is fully set forth in the following specication. v

This invention relates generally to machines for sewing, embroidering, or otherwise stitching fabrics, but has special reference to what are known as rotary-hook lock-stitch77 machines. In this class ot' machines the needleloop is carried around a stationary bobbin or shuttle, which is usualy contained in a suitable case.

The present invention comprises improvements, iirst, in the construction ot' the hook and bobbin-case, so as to avoid undue strain upon the'needle-loopin passing over the bobbincase, and thus to enable the tinestfabrics to he satisfactorily sewed; second, in the devices for producing the necessary tension upon the upper thread to enable the stitches to be properly tightened; third, in the take-up, which is of the rotary type; fourth, in the feed mechanism; and, lastly, in minor elements of the machine.

It is not necessary here to recite the construction of the various machines heretofore known and used, as the invention can be understood without Stich explanation, the particular improvements constituting the same being hereinafter fully set forth. Y

The following description will enable those Askilled in the art to which it appertains to make and use my invention, reference being had to the accompanying drawings, which form a part of this specification.

Figure l isa view in vertical longitudinal section, partly in elevation, ot' a machine embodying the invention; Fig. 2, an end view, partly in section, the rotary hook being removed; Fig. 3, a perspective view ot' the feedrocker with the retractile spring and other parts immediately connected therewith; Fig. 4, a plan view, partly in section, illustrating the construction of the take-up; Fig. eta, a perspective view ofthe fly-wheel carrying the takeup lever; Fig. 5, an elevation, partly in section, on the side opposite to that on which the operator takes his position; Fig. 6, views of the hook and bobbin-case detached; Fig. 7, views of another form of rotary take-u p that can be used in connection with other parts of the machine; Fig. 8,an enlarged view otthe automatic tension, with an adjusting device; Fig. Si, amoditication of the same; Fig. 9, a series of diagrams illustrating thc formation of -the stitch, and Fig. 10 a forni of bobbin-case with the open side toward the hook. Fig. 11 is a detail view, showing the end of the main shaft next the hook, with the eccentric-pins for operating the feed; and Fig. l2, a detail view, showing the devices for preventing dancing of the thread between the take-up and eye of the needle.

The same letters indicate like parts where they occur on all the figures.

A is the frame of the machine; B, the goose neck or arm; C, the cloth-plate; D, the vibratory needle-lever; E, the presser-bar; F, the

main shaft of the machine; Gr, a secondary shalt, and H a ily-wheel on the main-shaft. These two shafts have their bearings in the frame of the machine, and are connected with each otherbyt-hegearsf g, (see Fig.1,)ofwhich the former has just twice the number of teeth of the latter, so that the shaft G makes two revolutions to one of the shaft F. The needlelever is fulcrumed inthe goose-neck, and is vibrated by the eccentric d on the main shaft F and connecting-rod d2.

At the outer end ofthe goose-neck, or in the head of the machine, the needle-bar D is freeto move in suitable guides. It is connected with the needle-lever by a single pin, d3, which screws into a hole in the needlebar, and the ends of which rest in slots in the needle-lever. This pin d3 projects through a slot in the side ot' the head and prevents the turning of the bar. Other means, however, might be employed, as a spline on the bar arranged to tit in a corresponding groove. The needle is secured to the bar in any ordinary or suitable way. The nut d4, as shown, should be small enough in diameter to pass readily through the holes inv the Vhead of the machine, which serve as guides.

IOO

rocker7 while permitting sufficient endwise and vertical movement by means of a suitable recess or slot in the upper part of the rocker. The pin or eccentric m works in a slot in this rocker and imparts to it the vertical movement required in feeding. The eccentric-pin a works against a spring, n', fastened at one end to the rocker, so that it always restsV in contact with the pin n. Upon the side opposite to the latter it is cushioned by leather or othersuitablematerialmz. Therockerismoved forward to feed the fabric sewed by the pin a acting against the spring. It is returned by the spring p. cushion a2 is to avoid the noise which would beproduced by the striking of thepin a against the body of the rocker. A set-screw, q, regulates the length of the stitch. Other devices, such as an eccentric on a horizontal axis, could be used.

The 'feed-bar F2, carrying the feed-surface, is attached to the feed-rocker. The feed-surface is arched to correspond with the arc in which the rocker moves. The cloth-plate G or the throat-plate is similarly arched on its upper surface, as indicated by e8.

The hook G is secured to the end of the shaft Gr, and is rotated thereby. Its construction is best seen in Fig. 6. On the face it is recessed at 07 and at g, from which latter recess an opening, g2, extends to the periphery of the hook.

At g3 isthehook proper. In planit approximates the general shape of an oblique-angled parallelogram, being cut away or inclined in front and rear. The words front and rear7 are relative to the motion of the hook. It is cut away in front on the inside (to the right, Fig. l) and in the rear upon the outside. On the top, or side farthest from the center of the hook, is a triangular-shaped projection, g4, which extends backward, and which in operation catches the loop and prevents it from being drawn up too rapidly.

Two strips or cap-pieces, g5 gs, are secured on the face of the hook Gnear the periphery, so as to overhang the recess gl. One of these strips, gG, is preferably attached so as to be readily removed or turned aside, as shown in dotted lines, Fig. 6.

I is the bobbin or shuttle case, which holds the bobbin K and supports it on a central pin, t', whereon it is free to turn. The case is of a general cylindrical shape. Upon the side which fits against the hook, around two-thirds of the circumference, or thereabout, is a flange, f. The side away from the hook is preferably left open, so that the bobbin may be inserted and removed from the ease without taking the latter from the hook. A small wire, t2, is provided as a safeguard against accidental slipping out ofthe bobbin. The bobbin-case may, however, be closed on the outside and open toward the hook, as shown in Fig. l0; but in that case to take out the bobbin would require the removal of the case also. At i the side of the case is beveled in opposite directions,

The use ot' the spring` a and so as to guide the two parts of the loop on opposite sides ofthe case and bobbin. On top of the case is a small flat spring, 3, the free end of which bears on a projection on the case, over which the thread from the bobbin is passed from the hole i4. A small screw, i, is provided, which bears on the spring, so that by turning it the tension on the under thread can be readily changed. A flat extension, 5, upon the upper part of the case directs the loop and prevents it from catching when drawn u p. In this extension are holes t, through which the under thread is passed. By passing the thread through several holes the tension will be stronger than if it be passed through one hole only. These holes therefore furnish another means for regulating the tension on the under thread, which may be employed instead of or in addition to the screw if for varying the pressure of the spring 3.

In order to secure the bobbin in position in the hook, it is first placed in the bobbin-ease, and the stripgG being turned outward, as shown in dotted lines, Fig. 6, the flange t" is placed in the recess 07 under the projecting or overhanging edge of the strip g5, and the strip gs, being turned upward and secured, holds` the casein position on the hook. A projection, 7, on the case enters a groove on the stoppiece c, fastened to the under side of the clothplate. rIhe hook is free to revolve, and the bobbin-case is prevented from turning with it in either direction by the contact of the projection il against the stop-piece c.

The automatic tension is indicated by lV. (See Figs. l, S, and Se.)

Upon a vertical pin, ze, iixed on the arm or goose-neck of the machine isa slide, w', which is pressed upward by a springfw?. A collar, w3, attached to the rod V, which is reciproeated by an eccentric, c, on the main shalt F, encireles the slide wf, and by means of a circular projection thereon depresses it at each downward movement of the rod V. rlhe thread is held between the upper surface of the slide ze and the flat surface formed by the bottom of a small cup, held down by a spring, ai', the pressure of which is adjusted by a set-nut, wz. The part .r is formed cup-shaped in order to hold and conceal the spring. The slide w being automatic-all y depressed releases the thread at certain intervals and constitutes the automatic tension. By making the part against which the thread is held adjustable by means of a set-nut the tension can be readily regulated while sewing. A collar on the pin 'w limits the upward movement of the cup x. Instead of interposing the spring and cup or equivalent device, the thread could be held against the lower surface of the set-nut, if desired. The slide w is preferably in two parts, so that the upper may be able to turn freely, while the lower is held by the collar w3. In Fig. 8a the movement downward of the part x is limited. In this case the spring a" should be stronger than that marked @02.

At the back of the machine (see Fig. 5) is IOS IIO

a plate, y, to which the spring y (shown in dottedlines) is fastened at one end, thefree end projecting through a slot in the plate. This spring presses upon the upper thread on its way to the eye of the needle an d prevents its dancing.

In order to avoid irregularity in the tension on account ot the weight of or inequalities in the spool, a stiff wire, d, is secured to the needle-lever D, so as to project back of the automatic tension`and by its movement upward to unwind thread from the spool. The spool of thread is placed on the rod'z. The thread is then passed through the notch z', over the wire d, around. the pin w, between the slide w' and thercup fr, over the wire d", through ,the notch z2, under the plate y, around the rod z3, back under the spring y', through the notch zand thence to the hea-(hof themachine, in which itrests in a slot, z5. Itis then, after beingled between the disks of tension W', hereinafter described, passed through the eye ofthe needle from left to right, Fig. I;

The wire d may be shortened so as to act only on that portion of the thread between the notch z' and the automatic tension; but as the threading is easier and the danger of the threads coming underneath the wire is avoided, the construction shown is preferred.

The arm or goose-neck of the machine is slotted, as shown, so that the thread is concealed therein and protected. A groovein the upper surface ofthe goose-neck would serve a similar purpose. Thetake-upisformed byaprojection, h', on the side`0f the tiy-wheel H.

Referring to Figs. 1, 4, 4, and 5, a rightangled lever, h, is pivoted Ain a recess in the fly-wheel near its periphery, the pivot h2 being in line with one ot' the radii. The thickness ofthe wheel is such that the two arms of the lever are on opposite sides.

At h3 is a shield fixed to the machine-frame, and at h4 is a projection, formed preferably ot' leather, the two parts being arranged on opposite sides ot' the wheel and close toits surface. In passing by the shield h3 an arm of the bent lever comes into contact therewith, and is held so that the arm h forms a projection which is practically stationary on the wheel for the time being. lIhe length ot' the shield is calculated so that the slack loopthread is taken up when the iight-angled 1ever has just passed the end of the shield. The thread yielding no longer, it causes the rightangled leverto turn aside, and the thread is released from the end ot' the lever. If, in consequence ot' any accidental resistance in thel'ulrum ot' the lever, (dirt, dried oil, &c.,) the lever should not readily yield to the action of the thread, it passes in the next instant the projection h4, and, striking it, is turned aside so as to permit thc thread to slip off the lever. The rod z3 is bent so that the thread is drawn into the bend, where it is held directly in the path of the arm or projection h'. The thread is therefore caught and the slack l is taken up. When h strikes the projection h4 it is slackened again. The shield at the end which the leverlarm strikes so as to cause the arm h to project 'is preferably cushioned, so as to lessen the noise.

It is preferred that the projection h should catch the thread between the rod z3 and the needle, and not that from the automatic terr sion. Both threads may, however, be caught. In Fig. 7 the projection h is fixed on the Hywheel and is arranged to catch both threads. The rod or pin z", around which the thread is drawn, is placed below the periphery ot' the wheel. W'ith this construction the thread is slackened gradually, and not released at once.

In addition to the automatic tension which is placed between the spool-pin and take-up, an additional tension, W', is placed between the take-up and eye ot' the needle. This tension should be adjustable while sewing, and may be of ordinary or suitable construction, but is preferably intermittent in its action, so as to clutch the thread when it is required to act, and at other times to leave it free to be drawn up by the take-up. As shown, this tension is placed upon the head of the machine, and consists of two disks, y2, a thumb-screw, 1/3, for attaching them to the head of the ma chine, and a bent spring or elastic lever, 1/4. The spring or elastic lever is fastened at one end to the head of the machine, and the other end, being bent back, lies behind the inner ten' sion-disk. It is so disposed that it is struck by the end of the needle-lever while the needle is below the cloth-plate, and, being pressed outward, presses together the tension-disks y2, so that they clutch the thread between them. The pressure of the disks against each other is regulated by turning the screw g3. When the end of the needle-lever rises the pressure on the disks is relieved and they are allowed to separate and release the thread.

The additional tension W', when made intermittent in its action, as shown, might with propriety be called an automatic tension, as well as the tension WV, since the term automatic,77 as understood in the art and as employedin this specification, is intended to distin guish the tension W from ordinary tensions by the devices for automatically applying or releasing the tension' upon the thread at the proper' times; but for the sake of distinction the tension W is referred to herein as an intermittent tension.

The fly-wheel is or may be provided with a pulley for a belt. AS shown, a pinion, H, is also provided, which can be operated by a larger spur-wheel, with which is connected a handle or detachable treadle. H2 is a pin on which the bobbin is placed for winding.

the lower part of the presser-bar E the presserfoot E is secured by means of the single screw c. At the back of the foot is an extension, e', grooved and tittng over a spline, a3, on the head of the machine, which prevents the foot from turning and steadies it.

The under side .AtY

IOC

IIS

ot' the presser-foot is arched, as indicated by e2, so as to correspond with the curved surface of the cloth-plate and of the feed.

The operation of the machine is as follows: The bobbin K is filled by screwing it by means of a pivot-screw to the end of the main shaft and then turning the machine so that the thread coming from an ordinary spool pivoted on the table at a convenient distance behind the bobbin gradually lills it with the thread, and is then, with its case I, secured in position in the hook G by means of the strips g5 g6 and flange fi', as already explained, the thread being passed from the interior of the casethrou gh the hole i4, under the spring i3, out at one of the lower holes, i, and then back through the highest hole. The upper thread is passed through the tensions and through the eye of the needles, as before stated. The length of stitch is adjusted by the screw q. Motion being imparted to the main shaft F, the needle is caused to descend to the position marked I in Fig. 9. Upon the ascent of the needle the point of the hook enters the loop (see position II) and carries it around to position III, Where the loop is turned and divided by the beveled side t of the bobbin-case. NVhen the needle has reached its highest position the loop, owing to the revolution of the shaft G being more rapid than the main shaft, has been carried more than half-way round, as seen in position IV. Instead of dropping oft' the hook, it is caught by the projection g4, which retains it until the hook proper, g3, has passed the needle-hole and the needle is about to again penetrate the fabric. (See position V.) While the needle is still ascending the feed-surface is raised by the pin m, and before the needle has descended to position V the pin n has moved forward the rocker and advanced the fabric the distance of one stitch. As soon as the needle leaves the fabric the arm or projection h on the fly-wheel comes into contact with and begins to draw up the slack thread, and continues to do so until th'e needle just begins to enter the fabric again, when the' thread is released. The take-up will not ordinarily draw up the loop tight, but nearly so, or sufficiently to avoid slack loops, and to tighten the diminutive loop which remains and to complete the stitch the tension W is employed. When the needle is near the lowest point of its stroke the disks y2 are pressed together with a pressure adjusted to correspond with the work in hand and clutch the thread between them vuntil the hook, catching the next loop presented by the needle, tightens the former loop and completes the stitch. rlhe automatic tension is raised soon after the hook has caught the loop, and the thread continues comparatively loose until the needle passes out of the fabric. After position V the needle descends to position VI, and then to its lowest point, or position I, when the operations before described are repeated. When the needle descends the wire d is lifted,

and the automatic tension, being at that time closed, draws off from the spool, so that the thread required for each stitch is taken from the slack thread thus furnished. When, for any reason, it is desired to remove the needlebar to set the needle, or for other purpose, this can readily be done by unscrewing the pin d3. In passing aroundthe bobbin the loop is not pressed or subjected to tension between the bobbin and rotary hook, but moves freely in the recess g in the face of the latter.

Modifications may be made in the details ot' construction, as hereinbefore described.

It is obvious that parts of myinvention can be used without the others. For example, the take-up or feed or improvement in other parts could be adapted readily to machines of otherwise ordinaryor suitable construction; but it is preferred to combine the several parts, as already explained.

Having thus fully described my said invention, and the manner in which the same is or may be carried into effect, what I claim, and desire to secure by Letters Patent, is-

l. The combination, with a anged bobbincase, of a rotary hook provided with a groove for the tiange on the bobbin-case, a recess for the needle-loop back of said groove, and an opening leading from the aforesaid recess to the periphery ofthe hook in front of the hook proper, as set forth.

2. A rotary hook consisting of a disk provided with a groove and a recess back of said groove, as indicated, and the hook proper projecting from the disk near its circumference, and being beveled or cut away front and rear, an opening extending from the said recess to the periphery of the disk in front of the hook proper, substantially as described.

ln a rotary hook having an undercut groove for the reception of a flange on the bobbin-case, a strip or cap-piece pivoted to the hook and adapted to be swung into and out of position, for securing the bobbin-case in the hook, or for permitting its removal and replacement, substantially as described.

4. The combination, with a rotary hookv comprising a disk provided with an undercut groove and arecesslocated back of said groove, and the hook proper projecting from the said disk and being beveled or cut away in front and rear, of a bobbin-case having a flange,whereby it is secured in position in the hook, substantially as described.

5. The combination, with a grooved rotary hook recessed on its face back ot' the groove, and provided with an opening leading from said recess to the front of the hook proper, of a bobbin-case of general cylindrical form, having a flange at the end which is to be placed next the rotary hook, substantially as described.

6. A cylindrical bobbin-case and a rotary hook, With the hook proper equal in width to said case, and having on its upper surface a. retaining device for catching the needle-loop lIO ' pariill] g each -reciprocation of th `iie'dlebar, substa as it is drawn up, in combination with@ neeo the rotary lioo'k two revolutionsfor tially asdescribed. Y Y

7. In a rotary hook, the hook proper, having on top a backwardly-extendin g projcction,with its outer end free, substantially as described.

8. The triangular-shaped overhanging pror o jection on the hook, extending backwardth at is,in a direction opposite to its rotation-substantially as described.

9. A bobbin-case having on the outer side a dat extension beyond the periphery of the main body of the case, and provided with a tension-spring on the top of the case, behind the said extension, substantially as described.

10. The combination, with the fly-wheel of a sewing-machine, of a bent lever pivoted therein, and means, substantially as described,

for causing one arm of said lever to project during a portion of its revolution, as set forth.

11. Aflat cloth-plate arched at the throat,in combination with a presser-foot having the under side similarly arched, and an arc-of-thecircle feed, substantially as described.

l2. The combination, with the feed-rocker and eccentric-pin or device I'or operating the same, of a spring fastened at one end to said rocker, so as to bear at all times against said pinor device, and cushioned at the free end, where it comes into contact with the rocker through the movement of the pin'or device, substantially as described.

13. The combination, with an automatic tension, of an additional tension adj ustable while sewing, and arranged to act uponmthe thread between the take-up and eye of the needle, substantially as described.

14. The combiuation,with the needle,needle bar, and take-up of a sewing-machine, lof a tension device acting upon the upper thread between the take-up and spool-pin, an additional intermittent tension acting upon the same between the take-up a'n'd'ineedle-eye, and means, as indicated, for bringing said additional tension into action while the needle is below the cloth-plate, so that the formation of the next succeeding stitch tightens thesmall loop not drawn up by the take-up, substantially as described. p

15. The combination, in an automatic tension, of a stationary pin, a slide, devices for moving said slide at intervals lengthwise of said pin, a clamping-surface between which and said slide the thread is held, and a thumbnut engaging with a screw-thread on said pin and operating to adjust said clamping-surface, substantially as described.

16. A presser-foot for sewingmachines, pierced with a needle-hole and arched on the bottom in the direction of its length to correspond with the movement of the feed-surface in an arc-of-the-circlc feed, substantially as described.

17. rlhe combination, in a sewing-machine, with an eye-pointed needle and cooperating devices for locking an upper with an under thread, of a take-up, an automatic tension arranged to act upon the thread between the spool-pin and take-up, and an adj ustablc intermittent tension arranged to act upon the thread between the take-up and eye of the,

needle, substantially as described.

In testimony whereof I have signed this specification in the presence of two subscribing witnesses.

M. C. GRITZNER.

Witnesses:

J. ENGLERT, EDMUND M. SMITH. 

